Polyurethane molded roofing structures

ABSTRACT

The invention describes a structure including a first layer, a third layer and a second layer including a low side and a high side. The first layer comprises a low density polyurethane, the second layer comprises fiberglass and the third layer comprises a high density polyurethane. The first layer is reaction injection molded upon the low side and the third layer is reaction injection molded upon the high side.

RELATED APPLICATIONS

This application claims priority to United States Provisional Application 60/543023, filed Feb. 9, 2004.

BACKGROUND OF INVENTION Field of the Invention

The invention relates to roofing. More specifically, the invention relates to a molded roofing structure with fiberglass and polyurethane.

Roofing materials are used to construct roofs in residential and commercial buildings. Typically, roof construction is cost and labor intensive. Furthermore, roofing materials may be heavy, requiring substantial structural support. Additionally, roofing materials may be flammable and may poorly insulate the interior of the building from the environment. Poorly insulated roofing increases the cost of ownership of the building by increasing heating and cooling costs.

Reaction injection molding (RIM) is a process whereby at least 2 reactive liquid chemical components are mixed at high pressure and react to form a urethane. Typically, the chemical components include a polyol and an isocyanate, although other substances may be used. A RIM mixing head is mounted to a closed mold to contain the reaction agents and the resulting urethane will take the form of the mold. Molding pressures are kept to 100 psi or less, allowing the use of lower cost materials. Other molds may use atmospheric pressure. 1200-2500 psi pressures may exist in the mixing head that supply the reactants to the mold.

Geary discloses a tough and durable insulation board produced in part with scrap rubber materials and related methods in United States Patent Application Publication US2003/0082365A1 published on May 1, 2003. The Geary board includes a polyurethane foam core that further includes a filler of scrap rubber materials and fiberglass.

Shihadeh discloses a sealing composition for roofs and the like in U.S. Pat. No. 3,980,597 issued Sep. 14, 1976. The Shihadeh sealant includes polyurethane compounds with bituminous materials. The sealant is dehydrated and chemically neutralized and a self-supporting film is added.

Soto Losada discloses a self-carrying liner for the internal lining of vehicle ceilings in U.S. Pat. No. 6,423,655B1 issued Jul. 23, 2002. The Soto Losada liner includes a support structure with an outer liner layer. The support structure has 3 layers, with the middle layer considerably thicker than the decorative and support layers. The decorative layer is of a polyester liner. The layers are attached by preheating and without adhesives.

Hunter discloses a monolithic roofing surface membrane and applicators with a method for using the same in U.S. Pat. No. 6,416,854B2 issued Jul. 9, 2002. The Hunter membrane includes a spontaneously curable polymer with a mesh of fabric or fiberglass with a silicone coating.

A new roofing material addressing these, and other, limitations of the prior art is desirable.

SUMMARY OF THE INVENTION

The invention provides a structure including a first layer and a second layer including a low side and a high side, wherein the first layer comprises a low density polyurethane and the second layer comprises fiberglass. A third layer, comprises a high density polyurethane, and wherein the first layer is reaction injection molded upon the low side and the third layer is reaction injection molded upon the high side.

The foregoing and other features and advantages of the invention are apparent from the following detailed description of exemplary embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention;

FIG. 2 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention;

FIG. 3 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention;

FIG. 4 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention;

FIG. 5 is a side view illustrating one embodiment of a roofing structure in accordance with one aspect of the invention; and

FIG. 6 is a flowchart illustrating one embodiment of a method of manufacturing a structural element in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention at 100.

Roofing structure 100 includes a first layer 110, a second layer 120 and a third layer 130. First layer 110 includes an outer surface 115. Third layer 130 includes a lower surface 135.

Second layer 120 is a substantially rigid structure comprising fiberglass. Second layer 120, in one embodiment, serves to support the first and third layers. In another embodiment, second layer 120 separates the first and third layers during the molding process. Second layer 120 includes low side 118 and high side 128. After molding, low side 118 is adjacent first layer 110 and high side 128 is adjacent third layer 130. In one embodiment, second layer 120 comprises fiberglass. In another embodiment, second layer 120 comprises a substantially rigid material able to withstand the pressures and temperatures endemic to RIM processing.

First layer 110 is a layer of a low density polyurethane. In one embodiment, a filler is dispersed within the first layer 110. The filler may be rubber or recycled rubber, glass fiber, or fiberglass. Other fillers may also be used to obtain desired characteristics, such as heat reflection/retention, tensile or shear stability and weight.

In one embodiment, the outer surface 115 is molded to obtain a predetermined shape. For example, the outer surface 115 may be molded for a herring-bone appearance. In another example, outer surface 115 is molded for a shingled appearance.

Third layer 130 is a layer of high density polyurethane. In one embodiment, filler is dispersed within the third layer 130. The filler may be rubber or recycled rubber, glass fiber, or fiberglass. Other fillers may also be used to obtain desired characteristics, such as heat reflection/retention, tensile or shear stability and weight.

Those of ordinary skill in the art recognize the differences between low and high density polyurethanes. Although the terms “low” and “high” are relative, those of ordinary skill in the art are acquainted with the definitions, and this application uses those terms in accordance with their usage in the art.

Structure 100 is obtained by reaction injection molding (RIM) the first and third layers 110, 130 upon the second layer 120. The second layer 120 is positioned in the RIM mold with space on either side of second layer 120. Next, first layer 110 is RIM molded by injecting the space on one side of second layer 120 with the material for the first layer. After the first layer is cured, the third layer 130 is RIM molded by injecting the other side with the material for the third layer. Those of ordinary skill in the art will readily recognize that this process is suited for modification to run in an assembly line fashion, with multiple molds operating simultaneously, injecting one mold while a second mold is curing.

The structure results from casting of the mold, rather than by merely sandwiching multiple layers to form a product. It is important to note that the molding process creates a integral product that includes several layers, but that they layers are not separable after molding.

FIG. 2 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention at 200. Structure 200 contains first layer 110, second layer 120, and third layer 130. First layer 110, second layer 120 and third layer 130 may be implemented as the structures illustrated and discussed with respect to FIG. 1. Structure 200 further includes ventilation point 250. In one embodiment, structure 200 further includes a screen 260 disposed within ventilation point 250. In one embodiment, ventilation point 250 is a gap contiguously formed in the first layer 110, second layer 120 and third layers 130.

FIG. 3 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention at 300. Structure 300 contains first layer 110, second layer 120, and third layer 130. First layer 110, second layer 120 and third layer 130 may be implemented as the structures illustrated and discussed with respect to FIG. 1. Structure 300 further includes reception area 375. Reception area 375 is configured to receive a support beam (not shown), such that structure 300 may be dropped into place. In one embodiment, reception area 375 is configured to snap fit around a support beam.

FIG. 4 illustrates one embodiment of a roofing structure in accordance with one aspect of the invention at 400. Structure 400 is a top view of the outer surface molded in a predetermined shape.

FIG. 5 is a side view illustrating one embodiment of a roofing structure in accordance with one aspect of the invention at 500. FIG. 5 illustrates two structures joined at an apex in an A-frame configuration. The structures 500, in one embodiment, are implemented as structure 100 illustrated in FIG. 1. This A-frame configuration is one of many potential configurations of multiple structures 100.

FIG. 6 illustrates one embodiment of a method 600 of manufacturing a structural element in accordance with the instant invention. Method 600 begins at step 605. At step 610, a second layer comprising fiberglass is provided.

At step 620, a first layer comprising low-density polyurethane is RIM molded to the second layer.

At step 630, a third layer comprising high-density polyurethane is RIM molded to the second layer. In one embodiment, the third layer is molded to the side of the second layer opposite the side that the first layer was molded upon.

In one embodiment, step 640 is included in the method, wherein a reception area is formed and configured to receive a support beam.

Method 600 ends at step 645.

Use of one embodiment of the invention may result in a roofing structure that is fire-retardant, UV protected, heat insulated and a phonoinsulator. The product may also be used with solar energy panels as well as light panels. The invention may also include skylights, solar panels, heating and cooling exchangers.

While the preferred embodiments of the invention have been shown and described, numerous variations and alternative embodiments will occur to those of ordinary skill in the art. Accordingly, it is intended that the invention not be limited to as described, but also encompass the equivalents of the invention described, as well as any improvements which are obvious to those of ordinary skill in the art. 

1. A structure comprising: A first layer; A second layer including a low side and a high side; A third layer, wherein the first layer comprises a low density polyurethane, the second layer comprises fiberglass and the third layer comprises a high density polyurethane, and wherein the first layer is reaction injection molded upon the low side and the third layer is reaction injection molded upon the high side.
 2. The structure of claim 1 further comprising at least one reception area configured to receive a support beam.
 3. The structure of claim 2 wherein the reception area is formed in the third layer.
 4. The structure of claim 1 further comprising at least one ventilation point.
 5. The structure of claim 4 wherein the ventilation point further comprises a screen.
 6. The structure of claim 4 wherein the ventilation point comprises a gap contiguously formed in the first layer, second layer and third layers.
 7. The roofing structure of claim 1 wherein an outer surface is molded to a predetermined shape.
 8. The roofing structure of claim 7 wherein the external surface is a surface of the first layer opposite the second layer.
 9. A method of manufacturing a structural element, the method comprising: Providing a second layer comprising fiberglass; Reaction Injection Molding a first layer to the second layer, the first layer comprising a low density polyurethane; Reaction Injection Molding a third layer to the second layer, the third layer comprising a high density polyurethane.
 10. The method of claim 9 further comprising: Forming a reception area configured to receive a support beam. 